固定化解脂耶氏酵母处理油脂废水研究

利用海藻酸钙包埋固定的解脂耶氏酵母(Yarrowia lipolytica)分别降解以色拉油为惟一碳源和以葡萄糖为惟一碳源的污水，结果表明，在最佳处理条件下，固定化细胞在50 h内，能较好地降解废水中浓度为2 000 mg/L的色拉油和浓度为2 000 mg/L 的COD，降解率都在80%以上；固定化细胞对色拉油、COD降解效率随着时间的延长而增加、随着底物浓度的增加而下降；与未固定菌株相比，固定化细胞有着更好的储存稳定性和可重复使用性，结果进一步提示固定化解脂耶氏酵母适于含油废水以及高COD含量的生活污水处理。     

增强信心不辱使命--记全国安全生产工作会议

2002年1月15日至16日,全国安全生产工作会议在北京西郊宾馆召开。国务院副总理、国务院安全生产委员会主任吴邦国为大会做了批示:2002年安全生产任务更十分艰巨悄有松懈,安全事故又会大幅度上升。大会安排了新闻发布会,国家安全生产监督管理局局长张宝明、副局长闪淳昌等领导同志回答了记者提问。     

固定化白地霉处理高硬度及高矿化度岩溶水的研究

为了使白地霉固定化小球处理太原市地下岩溶水达到最佳絮凝效果,分别研究了白地霉菌体的最佳扩大培养条件.同时,分别选用海藻酸钠(SA)、聚乙烯醇-海藻酸钠(PVA-SA)及聚乙烯醇-海藻酸钠-明胶(PVA-SA-明胶)作为固定化剂,固定化白地霉菌体,进行絮凝性能分析.最后,确定了固定化小球处理岩溶水的最佳搅拌时间及投加量,并与六水合氯化铝、自制三元复合吸附剂及壳聚糖的5%冰醋酸溶液的絮凝效果进行了比较.结果表明,将白地霉种子培养基按3%的接种量接入白地霉扩大培养基3中进行扩大培养,可在第2d获取活性较好的大量白地霉菌体进行固定化.处理岩溶水时应选用PVA-SA-明胶固定化的白地霉小球,并在其投加量为4g·L-1、搅拌时间为60min时,对岩溶水矿化度、硬度的最大絮凝率分别为96.88%、50.00%.经与化学混凝剂絮凝性能对比发现,微生物絮凝剂具有操作简便、无二次污染、絮凝效果较好的优点.     

兰州市大气颗粒物多环芳烃的恒能量同步荧光光谱特征研究

通过传统单波长激发/发射荧光光谱法与恒能量同步荧光光谱法进行对比,对大气颗粒物中多环芳烃(PAHs)进行了定性定量分析,采用恒能量同步荧光光谱法在不同能量差下建立了15种典型PAHs成分的恒能量同步荧光法的标准谱库.在各PAHs在最佳能量差下进行定量分析,结果表明,除苊荧光信号响应较差外,其余PAHs的LOD和LOQ分别为0.0580～3.18、0.232～12.7 ng·mL~(-1).15种PAHs的空白和一定浓度下的加标回收率范围在82.8%～120.0%,相对标准偏差范围在0.51%～5.87%之间,以恒能量同步荧光光谱进行了兰州地区大气颗粒物中15种PAHs分布特征分析.     

洋河流域不同土地利用类型土壤硒(Se)分布及影响因素

基于洋河流域土地利用方式、海拔高度、土壤、植被类型等采集流域上下游171个代表性表层土壤(0~10 cm),系统地分析了土壤总硒(Se)含量、分布及影响因素.结果表明,洋河流域土壤总Se含量(以干重(dw)计,下同)在0.02~3.24mg·kg-1之间,几何平均值为0.30 mg·kg-1,高于北京平原(0.20 mg·kg-1)、河北平原(0.19 mg·kg-1)和全国平均值(0.29mg·kg-1).洋河流域少Se(0.13~0.18 mg·kg-1)土壤主要分布在怀安县、宣化县以及怀来县,多数地区土壤处于足Se水平(0.18~0.45 mg·kg-1),除此之外,在万全县、兴和县、天镇县及阳高县分布有富Se(0.45~2.0 mg·kg-1)土壤.不同土地利用类型中Se含量有所差异,Se平均含量由高到低分别为:林地城镇工矿用地草地农业用地,其中农业用地平均含量为0.28 mg·kg-1.成土母质、土壤类型对洋河流域Se含量影响较小.黏粒含量与洋河流域表层土壤中Se相关性最好.Se含量随海拔增高显著增加,随p H增加显著减小.TOC、Fe和Al含量也是影响土壤Se含量的重要因素.     

基于面积-高程积分的地下水动态分析——以泾惠渠灌区为例

为了研究泾惠渠灌区的地下水动态特征,探讨面积-高程积分在地下水动态分析中的可行性,利用ArcGIS空间分析工具计算了灌区地下水面积-高程积分数据,绘制了不同时期的地下水面积-高程积分曲线,分析了灌区地下水水位与储存量动态特征。结果显示:1978?—?2012年,泾惠渠灌区地下水面积-高程积分值为0.46、0.44、0.38、0.39,表明地下水水位与储存量整体呈下降趋势;1991?—?2012年,410.00?—?446.19 m水位区间面积由1978年的2.54下降为0,342.51?—?360.00 m水位区间面积多年持续增加,中等水位区间存在演化差异性,反映出不同时期地下水开发强度具有空间变异性;以1978年为基准,至2012年地下水储存量减少约7.08×10~8 m~3;降水、地表水引水量、人工开采是影响泾惠渠灌区地下水动态的重要因素,补排失衡是引起灌区地下水储存量下降的主要原因。研究表明:面积-高程积分曲线可以表征地下水水位空间结构特征和储存量的变化情况,利用面积-高程积分值能够近似估算地下水储存量变化量,证明了面积-高程积分在地下水动态研究中具有一定的实用性。     

聚苯乙烯微塑料对铜绿假单胞菌生物膜形成和结构变化的影响

微塑料在水环境中的污染情况日益严重,对水生生物的生长发育造成严重影响,而目前有关微塑料对生物膜形成影响机制的研究十分有限.为探究聚苯乙烯微塑料（PS-MPs）对铜绿假单胞菌生物膜形成发育的影响,选用不同浓度和粒径PS-MPs进行暴露试验,研究其对生物膜内生物量、氧化应激水平、生物膜结构和群体感应系统的影响.结果表明,PS-MPs诱导严重氧化应激反应并抑制生物膜形成和发育,粒径越小,产生的抑制作用越强烈,抑制效果表现为0.1 μm>0.5 μm≈1 μm>5 μm.PS-MPs通过与细胞接触造成严重物理损伤,形成的生物膜厚度显著减小且结构稳定性遭到破坏,膜内细菌通过分泌胞外聚合物来抵御PS-MPs的胁迫作用.PS-MPs进一步通过干扰铜绿假单胞菌群体感应系统,下调关键基因lasI、lasR、rhlI和rhlR的表达水平,抑制信号分子和相关毒力因子的合成与分泌,降低细菌对毒性作用的防御功能,最终影响生物膜形成和结构稳定性.     

Copper and Zinc in a paddy field and their potential ecological impacts affected by wastewater from a lead/zinc mine, P. R. China

As well known, at normal levels, copper and zinc are essential micronutrients for plants, animals, and humans. However, excessive Cu and Zn are toxic and disturb a wide range of biochemical and physiological processes. Using Atomic Absorption Spectrophotometer (AAS; Perkin-Elmer 3030, USA), soil and rice plant (Oryza sativa L.) samples collected from a paddy field in Lechang lead-zinc mine area, Guangdong Province, China were analyzed and their potential ecological impacts to local human and livestock were evaluated. The results showed that the paddy soils were contaminated with Cu and Zn. Both metals in soils had low bio-available fractions for paddy plants, animal and human by three chemically analytical techniques. Generally, were concentrations of copper and zinc root > straw > stalk > grain with hull > grain without hull (i.e. unpolished rice) and in the normal ranges indicating no ecological risk for local livestock and residents. All positive correlation coefficients, however, between heavy metals in rice plant and total, exchangeable (step 1 in Tessier's method established in 1979) and DTPA-extractable fractions in soils were found in this study indicating that elevated heavy metal in soils would increase long-term exposition and possible consequence of ecological hazard through food chains.     

Relationships among multiple trace elements in coastal Casuarina equisetifolia ecosystems on Hainan Island, South China

Forty-six trace elements in coastal Casuarina equisetifolia plant–soil systems at nine sampling sites on Hainan Island were analyzed using ICP-MS. The relationships among the trace elements of the same group or the same periodicity of the Periodic Table in the plants and soils were complex and no consistent patterns were found. More combinations of elements occurred with high positive correlation coefficients within the same periodicity than within the same group of the Periodic Table, and there were more high positive correlations in soils than in plants. However, there were many element combinations in Block d (transition elements) with high positive correlation coefficients in plants. Markedly high positive correlation coefficients between individual rare earth elements and Y and among Zr, Nb, Cd existed in both plants and soils. The dendrograms obtained by cluster analysis show that rare earth elements had very similar occurrence and distribution in both soils and plants. Thus, they behaved as a coherent group of elements both geochemically and biogeochemically. The transition elements were more coherent in plants than in soils.     

Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments

The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment.